Funds are requested for the purchase of a quantitative fluorescent imaging and photometry system with epi-fluorescent microscope to support the studies of five separately funded Nm projects. The instrument will have dual wavelength excitation and emission capability. Detection will be by high-speed photometric and computer-aided intensified CCD camera. Data acquisition and analysis will be coordinated by a dedicated microcomputer allowing quantitation of photon counting and/or image analysis. The first project deals with the cellular mechanisms which couple changes in O2 to changes in intracellular Ca++. The second project deals with the role of intracellular Ca++ and Na+ in the metabolic actions of growth hormone in adipose tissue. The third project deals with the myocardial actions of adenosine and catecholamines in controlling intracellular Ca++. The fourth project deals with the renal epithelial cell transport mechanisms involved in the control and actions of oxalate in the formation of kidney stones. The final project deals with the actions of lalpha,25- dihydroxy vitamin D on nuclear Ca++ and genomic regulation in bone cells. All of these projects share a common need to determine cellular fluorescent signals; a need that can be served by routine access to the spectrofluorimetric and imaging capability of the proposed instrument.